The present invention relates to a power supplying control circuit, and more particularly, to an improved power supplying control circuit in two systems which require a selective operation and own the same power supply jointly in order to detect an operation of one system and to automatically cut off the supply of power to the other system.
Generally, in most cases that two systems own one power supply jointly, means for controlling each drive of each system within their respective systems are included. That is, each system is separately driven. Such a system which requires a selection operation of each system, however, has several problems. For example, while one of the systems is operating, it is necessary to stop an operation of the other system. For example, a car audio system is usually included in the vehicle and a car phone system is also mounted. In this case, two systems own one power supply, for example, a battery jointly. If while the car audio system is operating a driver uses the car phone system, a sound output from the car audio system is a serious obstacle to use of the car phone. Thus, since he had to make an necessary operation to turn down the output of the car audio system or to out off the supply of power to the car audio system to use the car phone, a power of concentration on driving was decreased and thus, there was quite a possibility that an accident might happen.
FIG. 1 is a power supplying apparatus of the prior art including a car phone system 10 and a car audio system 20. In FIG. 1, two systems are connected to a power supply 30, i.e., a battery jointly and are operated independently. If while the car audio system 20 is operating a driver uses the car phone system, a sound output from the car audio system 20 is a serious obstacle to use of the car phone as shown above.